1. Field of the Invention
The present invention relates to a method for controlling a wearable robot, and more particularly, to a method for controlling a wearable robot attached to a joint part of a user.
2. Description of Related Art
In recent years, a wearable robot attached to a joint part such as a waist or a knee of a user has been developed and trials regarding its use have been conducted at working sites or rehabilitation sites. In such a wearable robot, a robot joint needs to be controlled so that the angle of the joint part of the user is within a given allowable angle range.
For example, Japanese Unexamined Patent Application Publication No. 2013-138793 discloses a wearable robot in which, when the angle of a robot joint (that is, the angle of a joint part of a user) goes outside of a given allowable angle range, the robot joint is controlled so that the angle of the robot joint is made to go back within the allowable angle range.
According to the wearable robot disclosed in Japanese Unexamined Patent Application Publication No. 2013-138793, when the angle of the robot joint is made to go back within the allowable angle range, the control to make the angle of the robot joint go back within the allowable angle range is ended, whereby the user is able to freely operate the joint part.
At this time, however, once a person starts a motion to move the joint part in one direction, the person cannot immediately stop the motion to move the joint part even when the angle of the joint part of the user is forced to go back within the allowable angle range. Therefore, the angle of the joint part of the user again goes outside of the allowable angle range. Such an operation is repeated, as shown in FIG. 7, at the boundary between the inside and the outside of the allowable angle range, which generates so-called hunting (oscillation) and thus makes the user feel uncomfortable.